ABSTRACT Background. The ALERT algorithm, an effective compression-only phone cardiopulmonary resuscitation (CPR) protocol has the potential to help bystanders initiate CPR. This study evaluates the psychological impact of the CPR’s practice on untrained persons (UP). Methods. This is a quasi experimental longitudinal study (n = 153). We used: demographics data, CPR’ emotional characteristics; the Peritraumatic Dissociative Experiences Questionnaire ; the Way of Coping Check List and the Impact of Event Scale. Findings. Two psychological profiles: UP at high risk to develop a post traumatic disorder (higher average scores ; high emotional distress during the CPR) versus UP at low risk. Discussion. These preliminary results highlight the importance of identifying the psychological profile of the UP. For a CPR, UP at high risk should be treated differently: first, take the time to reduce emotional distress and then only talk about the CPR. This step could reduce the risk for PTSD [less ▲]